Turbine blading



H. T. HERR TURBINE BLADING Filed May 51. 1922 12171917 INVENTOR ATTORNEY Patented th- 2, 1923,

,. a era E r n, his 5. \i ii HERBERT T: HERB; 0F PHILADELPHIA, rnnnsrnvanm, essrenoazro wns'rrnenousn nLEcTBIc AND narrower-"creme COMPAIQ'Y, a oonren'a'rron onP-nNnsYLvAnra j anaemia To all who met mtg)bow/00in: Be it known that l, llnnnr;

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citizen ofth'e United States, and a resident wvented a new and useful Improvement Turbine; Blading, of which the following'is a specification. f j My invent-ionirelatcs to turbine blading, more particularly of the type wherein a rela-; tively wide blade is adapted to receive steam transversely thereof a n'd "to"discharge the same longitudinallythereof and it hasfor its object to provideblades of the character des ignated which shall ibe irelatively light yet strong in construction. l

In the accompanying drawing,'.l*lig; 1 is a diagrammatic: sectional view. of a steam tur biiie embodying blading constructed in accordance with, my invention; 'Fig."2 is a transverse sectional view; and, 'F'ign3 is a plan view or one of the novel bladesfindicated in Fig.1. I v In the application of Alexander TJKasley, Serial No. 486,517, filed July 21, 1921, continned as Serial No. 521,872, filed December 12, 1921, and assigned to WVestinghouse Electric and Manufacturing Company, there is disclosed atype of wide exhaust blade which is adapted to receive steam axially of the turbine rotor and to discharge it peripherally. It is characteristic of the type of blading disclosed in this application that each blade comprises a main portion, sub

stantially plane in shape and disposed radially, and an outer curved or spoon-outline portion. In order to avoid the imposition of bending moments upon theinain plane portion of these blades, it is necessary to design the outer curved discharge portion or tip so that the center of gravity thereof shall lie in the medial plane of the main blade portion; and, in order to obtain such a 'distribwa tion of mass of each blade, as well as to provide for the design of an ei'licient fluid ex? panding channel at the blade tips, it has been necessary to increase the effective thickness at the point of maximum concavity. This necessary thickening has, in certain cases,

led to the inclusion of an unnecessarily large and heavy mass of material in the tips Wlth the imposition of severe centrifugal strains on the main portions of the blades when operated at high speeds;

Bearing inmind the necessity for a disstem I 192% s rialno. aeeaaef i" charger tip of"relative thicknessj order to provide'a proper discharge. channel and yet I which shall at sametim'e not unduly strain the main portion ofthe blade, I find that it s' desirabl'e to cpnstruct the. tip .oLt" two'or more pieces otsh ee't nietz'ildefining a;

chamber thcrebe'tween",thus providing; a

structurewhich is light, strong,'and susceptible o f'b'ei'ng. so shaped as to give maximum economy. v ,f l p Referring'now to the drawings for a more detailed description ofniy inventionpl show a turbine comprising a rotor 1 0 ,'having jo'urnalportions 11, fitting in bearings- 12, can ried by the casing or cylinder 13, the casing or cylinder and the rotor being provided with energy-abstracting elements for abs stra'cting energy'i roin' stcain supplied from 'the conduit l lnandf a-t'ter the r available en- .ergy isahstracted, the steam enters the exliaust chamber 15fwhi'ch communicates with a. suitable exhaust? outlet,'n ot shown 7 l I show the conduit 14 communicating with one" ormore nozzles 17 of a multi-velocity impulsei stage comprising movingrows of blades; 18, carried by the rotor 10, and arow of redirecting blades 19. interposed: therebetween. After being discharged from it he last row of moving blades 18,, the steam is then passes between the guide blades 22. for

entry between the wide exhaust blades 23, from which it is discharged peripherally to the exhaust chamber l5. :The particular con struction otthe bla ding 18, 19, 20 and 21, constitutes no partof invention and it is referred to tor illustrative purposes only.

The Wide exhaust blades 23 comprise inner substantially radial or plane portions 24 and outer curved or Symon-outline discharge portions 25, the latter being adaptedv to expand and discharge the =fluid'peripherally at a small angle. The blades 23 are preferably made up of a plurality of side-by-side sections 27 as indicated in Fig. l in order to facilitate manufacture.

The outer curved porti0ns 25 are formed oftvvo pieces of sheet metal 28 and 29 bent to the appropriate shapeflas shown, these two pieces of metal being appropriately 'joined as by Welding or brazing at the extreme'tip of'the blade and engaging the main portion Q i oi the blade on opposite sides-thereof as shoWn atS O. Preferably, p the engaging faces are serratedas, shown at 31 and rivets 32 are placed therethrough in order'ito attach the tip of the main portion-of the blade. f

Suitable lashing members may beprovided in the-form of edge Woundribbo-ns 34 suitably seated between adjacent bladelsejctio ns, these members being rigidly fastened;

as bybrazing, soldering "or r iyeting, so as. to largely eliminate vibration.

blade portion in apluralityvof different" Ways.

While I have shown my invention in but 'i one ar itwilljbeobvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications, Without departing from the spirit thereoflfand I desire therefore, that only such limitations shallbe placed there- 7 upon as are imposed by the prior art oras are specifically setforth in the appended claims; I Y

a-steam turbine rotor blade,the combination with spline b y anes; of a spoon-outline tip portion thereupon, .said' tip portion being hollow in construction and embracing the tip of saidbody po rtion.,-

2. Ina steam turbine rotor blade;ii,the combination with a plane body po'rtion bf a1 spoon-outline tip portion thereupon,- saidtip -portion being) formedv from two pieces of sheet metal jo-inedlat theirlouter edge and embracing the tip of said plane portion at their inner edges, said pieces of. sheet metal defin ng a hollow Space Within said tip portion.

3. In a steam turbine rotoi'ibladerthe binationn ith a plane body portion, of a' spoon-outline tip portion thereupomlsaidtip portion being hollow in construction 'andf embracing .the tip of saidbody portion;

portion to said body portion.

and fastening means for joining said tip 4c; In a turbine rotor constructionia series of blades .havingmaln plane body portions lying in radial planesand With thickened spoon-shaped tips "defining exhausting throats, said bladesibeing adapted to receive fluid axially'of the rotor and'toexhaust the same radially throu 'qhsaid throats, and said tip portions being formedhollow to minimize the Weight thereof. 7 or 7 i In testimony whereofll have hereunto subscribed myname this 25th day of May; 1922. i H

HERBERT T. 

